Compatibilized blends of alkenyl aromatic polymers, alpha-olefin/vinyl or vinylidene aromatic and/or sterically hindered aliphatic or cycloaliphatic vinyl or vinylidene interpolymers and styrenic block copolymers

ABSTRACT

A blend composition (and fabricated articles therefrom) comprising;  
     (A) one or more alkenyl aromatic polymers;  
     (B) one or more substantially random interpolymers comprising  
     (1) polymer units derived from;  
     (a) at least one vinyl or vinylidene aromatic monomer, or  
     (b) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or  
     (c) a combination of at least one aromatic vinyl or vinylidene monomer and at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, and  
     (2) polymer units derived from at least one of ethylene and/or a C 3-20 α-olefin; and  
     (3) polymer units derived from one or more of ethylenically unsaturated polymerizable monomers other than those derived from (1) and (2); and,  
     (C) one or more compatibilizers;  
     and wherein said blend has;  
     a) a tensile strength greater than 1500 psi;  
     b) a pull force test (⅛″ diameter) greater than 15 lb;  
     c) a Shore A Hardness greater than 79;  
     d) a cycle time in injection molding of less than 30 sec.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This Application claims priority from U.S. ProvisionalApplication No. 60/236,670 filed on Sep. 29, 2000, in the name of DaneChang et al., and U.S. Provisional Application No. 60/266,272 filed onFeb. 2, 2001 also in the name of Dane Chang et al., the entire contentsof both of which are herein incorporated by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not Applicable

FIELD OF THE INVENTION

[0003] This invention relates to thermoplastic blends comprising one ormore alkenyl aromatic polymers (Component A), one or more substantiallyrandom interpolymers (Component B) and one or more compatibilizers(Component C). Examples of such blends include blends of ethylenestyrene interpolymers (ESI) and/or ethylene propylene styrene (EPS)interpolymers with polystyrene (PS) and/or high impact polystyrene(HIPS) compatibilzed with SBS (styrene-butadiene-styrene) or SIS(styrene-isoprene-styrene) or SEBS (styrene-ethylene-butylene-styrene)or SEPS (styrene-ethylene-propylene-styrene) block copolymers.

[0004] This technology enables the production of novel materials with abalance of flexibility, degree of hardness, modulus, short cycle times(injection molding), tensile strength, pull force strength andpaintability.

BRIEF SUMMARY OF THE INVENTION

[0005] A blend composition (and fabricated articles therefrom)comprising;

[0006] (A) one or more alkenyl aromatic polymers;

[0007] (B) one or more substantially random interpolymers comprising

[0008] (1) polymer units derived from;

[0009] (a) at least one vinyl or vinylidene aromatic monomer, or

[0010] (b) at least one hindered aliphatic or cycloaliphatic vinyl orvinylidene monomer, or

[0011] (c) a combination of at least one aromatic vinyl or vinylidenemonomer and at least one hindered aliphatic or cycloaliphatic vinyl orvinylidene monomer, and

[0012] (2) polymer units derived from at least one of ethylene and/or aC₃₋₂₀ α-olefin; and

[0013] (3) polymer units derived from one or more of ethylenicallyunsaturated polymerizable monomers other than those derived from (1) and(2); and,

[0014] (C) one or more compatibilizers;

[0015] and wherein said blend has;

[0016] a) a tensile strength greater than 1500 psi;

[0017] b) a pull force test (⅛″ diameter) greater than 15 lb;

[0018] c) a Shore A Hardness greater than 79;

[0019] d) a cycle times in injection molding less than 30 sec.

DETAILED DESCRIPTION OF THE INVENTION

[0020] Definitions

[0021] All references herein to elements or metals belonging to acertain Group refer to the Periodic Table of the Elements published andcopyrighted by CRC Press, Inc., 1989. Also any reference to the Group orGroups shall be to the Group or Groups as reflected in this PeriodicTable of the Elements using the IUPAC system for numbering groups.

[0022] Any numerical values recited herein include all values from thelower value to the upper value in increments of one unit provided thatthere is a separation of at least 2 units between any lower value andany higher value. As an example, if it is stated that the amount of acomponent or a value of a process variable such as, for example,temperature, pressure, time and the like is, for example, from 1 to 90,preferably from 20 to 80, more preferably from 30 to 70, it is intendedthat values such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc. areexpressly enumerated in this specification. For values which are lessthan one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 asappropriate. These are only examples of what is specifically intendedand all possible combinations of numerical values between the lowestvalue and the highest value enumerated are to be considered to beexpressly stated in this application in a similar manner.

[0023] The term “hydrocarbyl” as employed herein means any aliphatic,cycloaliphatic, aromatic, aryl substituted aliphatic, aryl substitutedcycloaliphatic, aliphatic substituted aromatic, or aliphatic substitutedcycloaliphatic groups.

[0024] The term “hydrocarbyloxy” means a hydrocarbyl group having anoxygen linkage between it and the carbon atom to which it is attached.

[0025] The term “interpolymer” is used herein to indicate a polymerwherein at least two different monomers are polymerized to make theinterpolymer. This includes copolymers, terpolymers, etc.

[0026] The term “block copolymer” is used herein to mean elastomershaving at least one block segment of a hard polymer unit and at leastone block segment of a rubber monomer unit. However, the term is notintended to include thermoelastic ethylene interpolymers which are, ingeneral, random polymers. Preferred block copolymers contain hardsegments of styrenic-type polymers in combination with saturated orunsaturated rubber monomer segments. The structure of the blockcopolymers useful in the present invention is not critical and can be ofthe linear or radial type, either diblock or triblock, or anycombination of thereof.

[0027] Component A

[0028] For purposes of this invention, Component A is an alkenylaromatic polymer which is a melt-processable polymer or melt processableimpact-modified polymer in the form of polymerized vinyl aromaticmonomers as represented by the structure:

H₂C═CRAr

[0029] wherein R is hydrogen or an alkyl radical that preferably has nomore than three carbon atoms and Ar is an aromatic group. R ispreferably hydrogen or methyl, most preferably hydrogen. Aromatic groupsAr include phenyl and naphthyl groups. The aromatic group Ar may besubstituted. Halogen (such as Cl, F, Br), alkyl (especially C₁-C₄ alkylsuch as methyl, ethyl, propyl and t-butyl), C₁-C₄ haloalkyl (such aschloromethyl or chloroethyl) and alkoxyl (such as methoxyl or ethoxyl)substituents are all useful. Styrene, para-vinyl toluene, α-methylstyrene, 4-methoxy styrene, t-butyl styrene, chlorostyrene, vinylnaphthalene and the like are all useful vinyl aromatic monomers. Styreneis especially preferred.

[0030] The alkenyl aromatic polymer may be a homopolymer of a vinylaromatic monomer as described above. Polystyrene homopolymers are themost preferred alkenyl aromatic polymers. Interpolymers of two or morevinyl aromatic monomers are also useful.

[0031] Although not critical, the alkenyl aromatic polymer may have ahigh degree of syndiotactic configuration; i.e., the aromatic groups arelocated alternately at opposite directions relative to the main chainthat consists of carbon-carbon bonds. Homopolymers of vinyl aromaticpolymers that have syndiotacticity of 75% r diad or greater or even 90%r diad or greater as measured by ¹³C NMR are useful herein.

[0032] The alkenyl aromatic polymer may also contain repeating unitsderived from one or more other monomers that are copolymerizable withthe vinyl aromatic monomer. Suitable such monomers include N-phenylmaleimide; acrylamide; ethylenically unsaturated nitriles such asacrylonitrile and methacrylonitrile; ethylenically unsaturatedcarboxylic acids and anhydrides such as acrylic acid, methacrylic acid,fumaric anhydride and maleic anhydride; esters of ethylenicallyunsaturated acids such as C₁-C₈ alkyl acrylates and methacrylates, forexample n-butyl acrylate and methyl methacrylate; and conjugated dienessuch as butadiene or isoprene. The interpolymers of these types may berandom, block or graft interpolymers. Blends of interpolymers of thistype with homopolymers of a vinyl aromatic monomer can be used. Forexample, styrene/C₄-C₈ alkyl acrylate interpolymers andstyrene-butadiene interpolymers are particularly suitable as impactmodifiers when blended into polystyrene. Such impact-modifiedpolystyrenes are useful herein.

[0033] In addition, the alkenyl aromatic polymers include those modifiedwith rubbers to improve their impact properties. The modification canbe, for example, through blending, grafting or polymerization of a vinylaromatic monomer (optionally with other monomers) in the presence of arubber compound. Examples of such rubbers are homopolymers of C₄-C₆conjugated dienes such as butadiene or isoprene; ethylene/propyleneinterpolymers; interpolymers of ethylene, propylene and a nonconjugateddiene such as 1,6-hexadiene or ethylidene norbornene; C₄-C₆ alkylacrylate homopolymers or interpolymers, including interpolymers thereofwith a C₁-C₄ alkyl acrylate. The rubbers are conveniently prepared byanionic solution polymerization techniques or by free radical initiatedsolution, mass or suspension polymerization processes. Rubber polymersthat are prepared by emulsion polymerization may be agglomerated toproduce larger particles having a multimodal particle size distribution.

[0034] Preferred impact modified alkenyl aromatic polymers are preparedby dissolving the rubber into the vinyl aromatic monomer and anycomonomers and polymerizing the resulting solution, preferably whileagitating the solution so as to prepare a dispersed, grafted, impactmodified polymer having rubber domains containing occlusions of thematrix polymer dispersed throughout the resulting polymerized mass. Insuch products, polymerized vinyl aromatic monomer forms a continuouspolymeric matrix. Additional quantities of rubber polymer may be blendedinto the impact modified polymer if desired.

[0035] Commercial PS (polystyrene), General purpose polystyrene (GPPS),HIPS (high impact polystyrene), ABS (acrylonitrile-butadiene-styrene)and SAN (styrene-acrylonitrile) resins that are melt processable areparticularly useful in this invention.

[0036] Component B

[0037] The term “substantially random” (in the substantially randominterpolymer comprising polymer units derived from ethylene and one ormore α-olefin monomers with one or more vinyl or vinylidene aromaticmonomers and/or aliphatic or cycloaliphatic vinyl or vinylidenemonomers) as used herein means that the distribution of the monomers ofsaid interpolymer can be described by the Bernoulli statistical model orby a first or second order Markovian statistical model, as described byJ. C. Randall in POLYMER SEQUENCE DETERMINATION, Carbon-13 NMR Method,Academic Press New York, 1977, pp. 71-78. Preferably substantiallyrandom interpolymers do not contain more than 15 percent of the totalamount of vinyl aromatic monomer in blocks of vinyl aromatic monomer ofmore than 3 units. More preferably, the interpolymer is notcharacterized by a high degree of either isotacticity orsyndiotacticity. This means that in the carbon⁻¹³ NMR spectrum of thesubstantially random interpolymer the peak areas corresponding to themain chain methylene and methine carbons representing either meso diadsequences or racemic diad sequences should not exceed 75 percent of thetotal peak area of the main chain methylene and methine carbons.

[0038] The interpolymers used to prepare the injection molded articlesof the present invention include the substantially random interpolymersprepared by polymerizing i) ethylene and/or one or more α-olefinmonomers and ii) one or more vinyl or vinylidene aromatic monomersand/or one or more sterically hindered aliphatic or cycloaliphatic vinylor vinylidene monomers, and optionally iii) other polymerizableethylenically unsaturated monomer(s). Suitable α-olefins include forexample, α-olefins containing from 3 to about 20, preferably from 3 toabout 12, more preferably from 3 to about 8 carbon atoms. Particularlysuitable are ethylene, propylene, butene-1,4-methyl-1-pentene, hexene-1or octene-1 or ethylene in combination with one or more of propylene,butene-1, 4-methyl-1-pentene, hexene-1 or octene-1. These α-olefins donot contain an aromatic moiety.

[0039] Other optional polymerizable ethylenically unsaturated monomer(s)include norbornene and C₁₋₁₀ alkyl or C₆₋₁₀ aryl substitutednorbornenes, with an exemplary interpolymer beingethylene/styrene/norbornene.

[0040] Suitable vinyl or vinylidene aromatic monomers which can beemployed to prepare the interpolymers include, for example, thoserepresented by the following formula:

[0041] wherein R¹ is selected from the group of radicals consisting ofhydrogen and alkyl radicals containing from 1 to about 4 carbon atoms,preferably hydrogen or methyl; each R² is independently selected fromthe group of radicals consisting of hydrogen and alkyl radicalscontaining from 1 to about 4 carbon atoms, preferably hydrogen ormethyl; Ar is a phenyl group or a phenyl group substituted with from 1to 5 substituents selected from the group consisting of halo,C₁₋₄-alkyl, and C₁₋₄-haloalkyl; and n has a value from zero to about 4,preferably from zero to 2, most preferably zero. Exemplary vinylaromatic monomers include styrene, vinyl toluene, α-methylstyrene,t-butyl styrene, chlorostyrene, including all isomers of thesecompounds, and the like. Particularly suitable such monomers includestyrene and lower alkyl- or halogen-substituted derivatives thereof.Preferred monomers include styrene, α-methyl styrene, the loweralkyl-(C₁-C₄) or phenyl-ring substituted derivatives of styrene, such asfor example, ortho-, meta-, and para-methylstyrene, the ring halogenatedstyrenes, para-vinyl toluene or mixtures thereof, and the like. A morepreferred aromatic vinyl monomer is styrene.

[0042] By the term “sterically hindered aliphatic or cycloaliphaticvinyl or vinylidene compounds”, it is meant addition polymerizable vinylor vinylidene monomers corresponding to the formula:

[0043] wherein A¹ is a sterically bulky, aliphatic or cycloaliphaticsubstituent of up to 20 carbons, R¹ is selected from the group ofradicals consisting of hydrogen and alkyl radicals containing from 1 toabout 4 carbon atoms, preferably hydrogen or methyl; each R² isindependently selected from the group of radicals consisting of hydrogenand alkyl radicals containing from 1 to about 4 carbon atoms, preferablyhydrogen or methyl; or alternatively R¹ and A¹ together form a ringsystem. Preferred aliphatic or cycloaliphatic vinyl or vinylidenecompounds are monomers in which one of the carbon atoms bearingethylenic unsaturation is tertiary or quaternary substituted. Examplesof such substituents include cyclic aliphatic groups such as cyclohexyl,cyclohexenyl, cyclooctenyl, or ring alkyl or aryl substitutedderivatives thereof, tert-butyl, norbornyl, and the like. Most preferredaliphatic or cycloaliphatic vinyl or vinylidene compounds are thevarious isomeric vinyl-ring substituted derivatives of cyclohexene andsubstituted cyclohexenes, and 5-ethylidene-2-norbornene. Especiallysuitable are 1-, 3-, and 4-vinylcyclohexene. Simple linear non-branchedα-olefins including for example, α-olefins containing from 3 to about 20carbon atoms such as propylene, butene-1, 4-methyl-1-pentene, hexene-1or octene-1 are not examples of sterically hindered aliphatic orcycloaliphatic vinyl or vinylidene compounds.

[0044] One method of preparation of the substantially randominterpolymers includes polymerizing a mixture of polymerizable monomersin the presence of one or more metallocene or constrained geometrycatalysts in combination with various cocatalysts, as described inEP-A-0,416,815 by James C. Stevens et al. and U.S. Pat. No. 5,703,187 byFrancis J. Timmers, both of which are incorporated herein by referencein their entirety. Preferred operating conditions for suchpolymerization reactions are pressures from atmospheric up to 3000atmospheres and temperatures from −30° C. to 200° C. Polymerizations andunreacted monomer removal at temperatures above the autopolymerizationtemperature of the respective monomers may result in formation of someamounts of homopolymer polymerization products resulting from freeradical polymerization.

[0045] Examples of suitable catalysts, co catalysts, and methods forpreparing the substantially random interpolymers are disclosed in U.S.application Ser. No. 702,475, filed May 20, 1991 (EP-A-514,828); as wellas U.S. Pat. Nos. 5,055,438; 5,057,475; 5,096,867; 5,064,802; 5,132,380;5,189,192; 5,321,106; 5,347,024; 5,350,723; 5,374,696; 5,399,635;5,470,993; 5,703,187; 5,721,185, 5,919,983 and 6,150,297, all of whichpatents and applications are incorporated herein by reference.

[0046] The substantially random α-olefin/vinyl aromatic interpolymerscan also be prepared by the methods described in JP 07/278230 employingcompounds shown by the general formula

[0047] where Cp¹ and Cp² are cyclopentadienyl groups, indenyl groups,fluorenyl groups, or substituents of these, independently of each other;R¹ and R² are hydrogen atoms, halogen atoms, hydrocarbon groups withcarbon numbers of 1-12, alkoxyl groups, or aryloxyl groups,independently of each other; M is a group IV metal, preferably Zr or Hf,most preferably Zr; and R³ is an alkylene group or silanediyl group usedto cross-link Cp¹ and Cp²).

[0048] The substantially random α-olefin/vinyl aromatic interpolymerscan also be prepared by the methods described by John G. Bradfute et al.(W. R. Grace & Co.) in WO 95/32095; by R. B. Pannell (Exxon ChemicalPatents, Inc.) in WO 94/00500; and in Plastics Technology, p. 25(September 1992), all of which are incorporated herein by reference intheir entirety.

[0049] Also suitable are the substantially random interpolymers whichcomprise at least one α-olefin/vinyl aromatic/vinyl aromatic/α-olefintetrad disclosed in U.S. application Ser. No. 08/708,869 filed Sep. 4,1996 and WO 98/09999 both by Francis J. Timmers et al. Theseinterpolymers contain additional signals in their carbon-13 NMR spectrawith intensities greater than three times the peak to peak noise. Thesesignals appear in the chemical shift range 43.70-44.25 ppm and 38.0-38.5ppm. Specifically, major peaks are observed at 44.1, 43.9, and 38.2 ppm.A proton test NMR experiment indicates that the signals in the chemicalshift region 43.70-44.25 ppm are methine carbons and the signals in theregion 38.0-38.5 ppm are methylene carbons.

[0050] Further preparative methods for the interpolymers used in thepresent invention have been described in the literature. Longo andGrassi (Makromol. Chem., Volume 191, pages 2387 to 2396 [1990]) andD'Anniello et al. (Journal of Applied Polymer Science, Volume 58, pages1701-1706 [1995]) reported the use of a catalytic system based onmethylalumoxane (MAO) and cyclopentadienyltitanium trichloride (CpTiCl₃)to prepare an ethylene-styrene copolymer. Xu and Lin (Polymer Preprints,Am. Chem. Soc., Div. Polym. Chem.) Volume 35, pages 686,687 [1994]) havereported copolymerization using a MgCl₂/TiCl₄/NdCl₃/Al(iBu)₃ catalyst togive random copolymers of styrene and propylene. Lu et al (Journal ofApplied Polymer Science, Volume 53, pages 1453 to 1460 [1994]) havedescribed the copolymerization of ethylene and styrene using aTiCl₄/NdCl₃/MgCl₂/Al(Et)₃ catalyst. Sernetz and Mulhaupt, (Macromol.Chem. Phys., v. 197, pp. 1071-1083, 1997) have described the influenceof polymerization conditions on the copolymerization of styrene withethylene using Me₂Si(Me₄Cp)(N-tert-butyl)TiCl₂/methylaluminoxaneZiegler-Natta catalysts. Copolymers of ethylene and styrene produced bybridged metallocene catalysts have been described by Arai, Toshiaki andSuzuki (Polymer Preprints, Am. Chem. Soc., Div. Polym. Chem.) Volume 38,pages 349, 350 [1997]) and in U.S. pat. No. 5,652,315, issued to MitsuiToatsu Chemicals, Inc. The manufacture of α-olefin/vinyl aromaticmonomer interpolymers such as propylene/styrene and butene/styrene aredescribed in U.S. Pat. No. 5,244,996, issued to Mitsui PetrochemicalIndustries Ltd or U.S. pat. No. 5,652,315 also issued to MitsuiPetrochemical Industries Ltd or as disclosed in DE 197 11 339 A1 toDenki Kagaku Kogyo KK. All the above methods disclosed for preparing theinterpolymer component are incorporated herein by reference. The randomcopolymers of ethylene and styrene as disclosed in Polymer Preprints Vol39, No. 1, March 1998 by Toru Aria et al. can also be employed as blendcomponents for the injection molded articles of the present invention.

[0051] While preparing the substantially random interpolymer, an amountof atactic vinyl aromatic homopolymer may be formed due tohomopolymerization of the vinyl aromatic monomer at elevatedtemperatures. The presence of vinyl aromatic homopolymer is in generalnot detrimental for the purposes of the present invention and can betolerated. The vinyl aromatic homopolymer may be separated from theinterpolymer, if desired, by extraction techniques such as selectiveprecipitation from solution with a non solvent for either theinterpolymer or the vinyl aromatic homopolymer. For the purpose of thepresent invention it is preferred that no more than 30 weight percent,preferably less than 20 weight percent based on the total weight of theinterpolymers of atactic vinyl aromatic homopolymer is present.

[0052] Component C (Compatibilizer)

[0053] Suitable unsaturated block copolymers include those representedby the following formulas:

A—B—R(—B—A)_(n)  Formula I

[0054] or

A_(x)—(BA—)_(y)—BA  Formula II

[0055] wherein each A is a polymer block comprising a vinyl aromaticmonomer, preferably styrene, and each B is a polymer block comprising aconjugated diene, preferably isoprene or butadiene, and optionally avinyl aromatic monomer, preferably styrene; R is the remnant of amultifunctional coupling agent; n is an integer from 1 to 5; x is zeroor 1; and y is a real number from zero to 4.

[0056] The preparation of the block copolymers useful herein is not thesubject of the present invention. Methods for the preparation of suchblock copolymers are known in the art. Suitable catalysts for thepreparation of useful block copolymers with unsaturated rubber monomerunits include lithium based catalysts and especially lithium-alkyls.U.S. Pat. No. 3,595,942 describes suitable methods for hydrogenation ofblock copolymers with unsaturated rubber monomer units to from blockcopolymers with saturated rubber monomer units. The structure of thepolymers is determined by their methods of polymerization. For example,linear polymers result by sequential introduction of the desired rubbermonomer into the reaction vessel when using such initiators aslithium-alkyls or dilithiostilbene and the like, or by coupling a twosegment block copolymer with a difunctional coupling agent. Branchedstructures, on the other hand, may be obtained by the use of suitablecoupling agents having a functionality with respect to the blockcopolymers with unsaturated rubber monomer units of three or more.Coupling may be effected with multifunctional coupling agents such asdihaloalkanes or alkenes and divinyl benzene as well as with certainpolar compounds such as silicon halides, siloxanes or esters ofmonohydric alcohols with carboxylic acids. The presence of any couplingresidues in the polymer may be ignored for an adequate description ofthe block copolymers forming a part of the composition of thisinvention.

[0057] Suitable block copolymers having unsaturated rubber monomer unitsincludes, but is not limited to, styrene-butadiene (SB),styrene-isoprene(SI), styrene-butadiene-styrene (SBS),styrene-isoprene-styrene (SIS),α-methylstyrene-butadiene-α-methylstyrene andα-methylstyrene-isoprene-α-methylstyrene.

[0058] The styrenic portion of the block copolymer is preferably apolymer or interpolymer of styrene and its analogs and homologsincluding α-methylstyrene and ring-substituted styrenes, particularlyring-methylated styrenes. The preferred styrenics are styrene andα-methylstyrene, and styrene is particularly preferred.

[0059] Block copolymers with unsaturated rubber monomer units maycomprise homopolymers of butadiene or isoprene or they may comprisecopolymers of one or both of these two dienes with a minor amount ofstyrenic monomer.

[0060] Preferred block copolymers with saturated rubber monomer unitscomprise at least one segment of a styrenic unit and at least onesegment of an ethylene-butene or ethylene-propylene copolymer. Preferredexamples of such block copolymers with saturated rubber monomer unitsinclude styrene/ethylene-butene copolymers, styrene/ethylene-propylenecopolymers, styrene/ethylene-butene/styrene (SEBS) copolymers,styrene/ethylene-propylene/styrene (SEPS) copolymers.

[0061] Hydrogenation of block copolymers with unsaturated rubber monomerunits is preferably effected by use of a catalyst comprising thereaction products of an aluminum alkyl compound with nickel or cobaltcarboxylates or alkoxides under such conditions as to substantiallycompletely hydrogenate at least 80 percent of the aliphatic double bondswhile hydrogenating no more than 25 percent of the styrenic aromaticdouble bonds. Preferred block copolymers are those where at least 99percent of the aliphatic double bonds are hydrogenated while less than 5percent of the aromatic double bonds are hydrogenated.

[0062] The proportion of the styrenic blocks is generally between 8 and65 percent by weight of the total weight of the block copolymer.Preferably, the block copolymers contain from 10 to 35 weight percent ofstyrenic block segments and from 90 to 65 weight percent of rubbermonomer block segments, based on the total weight of the blockcopolymer.

[0063] The average molecular weights of the individual blocks may varywithin certain limits. In most instances, the styrenic block segmentswill have number average molecular weights in the range of 5,000 to125,000, preferably from 7,000 to 60,000 while the rubber monomer blocksegments will have average molecular weights in the range of 10,000 to300,000, preferably from 30,000 to 150,000. The total average molecularweight of the block copolymer is typically in the range of 25,000 to250,000, preferably from 35,000 to 200,000.

[0064] Further, the various block copolymers suitable for use in thepresent invention may be modified by graft incorporation of minoramounts of functional groups, such as, for example, maleic anhydride byany of the methods well known in the art.

[0065] Block copolymers useful in the present invention are commerciallyavailable, such as, for example, supplied by Shell Chemical Companyunder the designation of KRATON™ and supplied by Dexco Polymers underthe designation of VECTOR™.

[0066] Also suitable as compatibilizers are high styrene contentsubstantially ramdom interpolymers having

[0067] Additives such as antioxidants (e.g., hindered phenolics (e.g.,Irganox® 1010), phosphites (e.g., Irgafos® 168)), cling additives (e.g.,PIB), antiblock additives, colourants, pigments, fillers, and the likecan also be included in the present compositions, to the extent thatthey do not interfere with the enhanced properties discovered byApplicants.

[0068] The compositions of the present invention are compounded by anyconvenient method, including dry blending the individual components andsubsequently melt mixing, either directly in the extruder or mill usedto make the finished article (e.g., the automotive part), or by pre-meltmixing in a separate extruder or mill (e.g., a Banbury mixer).

[0069] There are many types of molding operations which can be used toform useful fabricated articles or parts from the present compositions,including various injection molding processes (e.g., that described inModem Plastics Encyclopedia/89, Mid October 1988 Issue, Volume 65,Number 11, pp. 264-268, “Introduction to Injection Molding” and on pp.270-271, “Injection Molding Thermoplastics”, the disclosures of whichare incorporated herein by reference) and blow molding processes (e.g.,that described in Modern Plastics Encyclopedia/89, Mid October 1988Issue, Volume 65, Number 11, pp. 217-218,“Extrusion-Blow Molding”, thedisclosure of which is incorporated herein by reference) and profileextrusion.

[0070] Some of the fabricated articles include toys, sports articles,containers such as for food or other household articles, footware,automotive articles, such as soft facia, sealants and assemblyadhesives.

[0071] Properties of the Interpolymers and Blend Compositions of thePresent Invention

[0072] The blends comprise:

[0073] 1) greater than about 20, preferably of from about 20 to about70, most preferably of from about 25 to about 55 weight %, (based on thecombined weights of substantially random interpolymer, the alkenylaromatic homopolymers or copolymer and the compatibilizer) of one ormore alkenyl aromatic polymers (Component A);

[0074] 2) of from about 20 to about 70, preferably of from about 25 toabout 65, most preferably of from about 30 to about 60 weight % (basedon the combined weights of substantially random interpolymer, thealkenyl aromatic homopolymers or copolymer and the compatibilizer) ofone or more substantially random interpolymers (Component B); and

[0075] 3) of from about 1 to about 30, preferably of from about 5 toabout 25, most preferably of from about 10 to about 20 weight % (basedon the combined weights of substantially random interpolymer, thealkenyl aromatic homopolymers or copolymer and the compatibilizer) ofone or more compatibilizers (Component C).

[0076] The molecular weight (Mw) of the alkenyl aromatic homopolymers orcopolymers used to prepare the blends of the present invention is fromabout 100,000 to about 500,000, preferably from about 120,000 to about350,000, more preferably 130,000 to 325,000.

[0077] The alkenyl aromatic polymer material used to prepare the blendsof the present invention comprises greater than 50 and preferablygreater than 70 weight percent alkenyl aromatic monomeric units. Morepreferably, the alkenyl aromatic polymer material is comprised entirelyof alkenyl aromatic monomeric units. Most preferably the alkenylaromatic polymer material is General Purpose Polystyrene (GPPS) or HighImpact Polystyrene (HIPS).

[0078] Component B comprises substantially random interpolymers ofα-olefin monomers, vinyl aromatic monomers and, optionally, additionalcomonomers including ethylene/styrene copolymers and terpolymers withα-olefins (especially propylene). The substantially random interpolymerscontain from about 0.5 to 15, preferably from about 3 to about 10, morepreferably from about 5 to about 8 mole percent of at least one vinyl orvinylidene aromatic monomer and/or aliphatic or cycloaliphatic vinyl orvinylidene monomer and from about 85 to about 99.5, preferably fromabout 90 to about 97, more preferably from about 92 to about 95 molepercent of ethylene and/or at least one aliphatic α-olefin having from 3to about 20 carbon atoms.

[0079] Component C comprises styrene block copolymers with greater than20, preferably 25-60 and most preferably 30-50 weight percent styrene;and/or substantially random interpolymers with 10-39, preferably 15-33,most preferably 17-31 mole percent vinyl aromatic monomer, with theproviso that the substantially random interpolymer compatibilizer isother than that used as Component B.

[0080] The blends of this invention may be processed by any knownfabrication techniques (including, but not limited to, injectionmolding, compression molding, extrusion, calendering, thermoforming andfoaming) to produce articles of suitable morphology that exhibit thefollowing properties:

[0081] Tensile strength greater than 1500, preferably >1700, mostpreferably >1900 psi

[0082] Pull force test (⅛″ diameter): >15, preferably >17, morepreferably >21, even more preferably >30, most preferably >40 lb

[0083] Shore A Hardness greater than 79, preferably >82 and mostpreferably >84

[0084] Cycle times in injection molding: <30, preferably <28, mostpreferably <26 sec

[0085] Paintable score of 5 according to ASTM Method D-3359.

[0086] The melt index (I₂) of the substantially random interpolymersused to prepare the blends of the present invention is from about 0.01to about 1000, preferably of from about 0.3 to about 30, more preferablyof from about 0.5 to about 10 g/10 min.

[0087] The molecular weight distribution (M_(w)/M_(n)) of thesubstantially random interpolymer used to prepare the blends of thepresent invention is from about 1.5 to about 20, preferably of fromabout 1.8 to about 10, more preferably of from about 2 to about 5.

[0088] In addition, minor amounts of alkenyl aromatic homopolymers orcopolymers having a molecular weight of about 2,000 to about 50,000,preferably from about 4,000 to about 25,000 can be added in an amountnot exceeding about 20 wt % (based on the combined weights ofsubstantially random interpolymer and the various alkenyl aromatichomopolymers or copolymers).

[0089] The following examples are illustrative of the invention, but arenot to be construed as to limiting the scope thereof in any manner.

EXAMPLES

[0090] Test Methods

[0091] a) Melt Flow Measurements

[0092] The molecular weight of the substantially random interpolymersused in the present invention is conveniently indicated using a meltindex measurement according to ASTM D-1238, Condition 190° C./2.16 kg(formally known as “Condition (E)” and also known as I₂) was determined.Melt index is inversely proportional to the molecular weight of thepolymer. Thus, the higher the molecular weight, the lower the meltindex, although the relationship is not linear.

[0093] b) Styrene Analyses

[0094] Interpolymer styrene content and atactic polystyreneconcentration can be determined using proton nuclear magnetic resonance(¹H NMR) or by ¹³C nuclear magnetic resonance.

[0095] All proton NMR samples were prepared in1,1,2,2-tetrachloroethane-d₂ (TCE-d₂). The resulting solutions were1.6-3.2 percent polymer by weight. Melt index (I₂) was used as a guidefor determining sample concentration. Thus when the I₂ was greater than2 g/10 min, 40 mg of interpolymer was used; with an I₂ between 1.5 and 2g/10 min, 30 mg of interpolymer was used; and when the I₂ was less than1.5 g/10 min, 20 mg of interpolymer was used. The interpolymers wereweighed directly into 5 mm sample tubes. A 0.75 mL aliquot of TCE-d₂ wasadded by syringe and the tube was capped with a tight-fittingpolyethylene cap. The samples were heated in a water bath at 85° C. tosoften the interpolymer. To provide mixing, the capped samples wereoccasionally brought to reflux using a heat gun.

[0096] Proton NMR spectra were accumulated on a Varian VXR 300 with thesample probe at 80° C., and referenced to the residual protons of TCE-d₂at 5.99 ppm. The delay times were varied between 1 second, and data wascollected in triplicate on each sample. The following instrumentalconditions were used for analysis of the interpolymer samples:

[0097] Varian VXR-300, standard ¹H:

[0098] Sweep Width, 5000 Hz

[0099] Acquisition Time, 3.002 sec

[0100] Pulse Width, 8 μsec

[0101] Frequency, 300 MHz

[0102] Delay, 1 sec

[0103] Transients, 16

[0104] The total analysis time per sample was about 10 minutes.

[0105] Initially, a ¹H NMR spectrum for a sample of the polystyrene,STYRON™ 680 (available from the Dow Chemical Company, Midland, Mich.)was acquired with a delay time of one second. The protons were“labeled”: b, branch; a, alpha; o, ortho; m, meta; p, para, as shown inFIG. 1.

[0106] Integrals were measured around the protons labeled in FIG. 1; the‘A’ designates aPS. Integral A_(7.1)(aromatic, around 7.1 ppm) isbelieved to be the three ortho/para protons; and integral A_(6.6)(aromatic, around 6.6 ppm) the two meta protons. The two aliphaticprotons labeled α resonate at 1.5 ppm; and the single proton labeled bis at 1.9 ppm. The aliphatic region was integrated from about 0.8 to 2.5ppm and is referred to as A_(al). The theoretical ratio for A_(7.1):A_(6.6): A_(al) is 3:2:3, or 1.5:1:1.5, and correlated very well withthe observed ratios for the Styron™ 680 sample for several delay timesof 1 second. The ratio calculations used to check the integration andverify peak assignments were performed by dividing the appropriateintegral by the integral A_(6.6) Ratio A_(r) is A_(7.1)/A_(6.6).

[0107] Region A_(6.6) was assigned the value of 1. Ratio Al is integralA_(al)/A_(6.6). All spectra collected have the expected 1.5:1:1.5integration ratio of (o+p):m:(α+b). The ratio of aromatic to aliphaticprotons is 5 to 3. An aliphatic ratio of 2 to 1 is predicted based onthe protons labeled α and b respectively in FIG. 1. This ratio was alsoobserved when the two aliphatic peaks were integrated separately.

[0108] For the ethylene/styrene interpolymers, the ¹H NMR spectra usinga delay time of one second, had integrals C_(7.1), C_(6.6), and C_(al)defined, such that the integration of the peak at 7.1 ppm included allthe aromatic protons of the copolymer as well as the o & p protons ofaPS. Likewise, integration of the aliphatic region C_(al) in thespectrum of the interpolymers included aliphatic protons from both theaPS and the interpolymer with no clear baseline resolved signal fromeither polymer. The integral of the peak at 6.6 ppm C_(6.6) is resolvedfrom the other aromatic signals and it is believed to be due solely tothe aPS homopolymer (probably the meta protons). (The peak assignmentfor atactic polystyrene at 6.6 ppm (integral A_(6.6)) was made basedupon comparison to the authentic sample STYRON™ 680.) This is areasonable assumption since, at very low levels of atactic polystyrene,only a very weak signal is observed here. Therefore, the phenyl protonsof the copolymer must not contribute to this signal. With thisassumption, integral A_(6.6) becomes the basis for quantitativelydetermining the aPS content.

[0109] The following equations were then used to determine the degree ofstyrene incorporation in the ethylene/styrene interpolymer samples:

(C Phenyl)=C_(7.1)+A_(7.1)−(1.5×A_(6.6))

(C Aliphatic)=C_(al)−(15×A_(6.6))

s_(c)=(C Phenyl)/5

e_(c)=(C Aliphatic−(3×s_(c)))/4

E=e_(c)/(e_(c)+s_(c))

S_(c)=s_(c)/(e_(c)+s_(c))

[0110] and the following equations were used to calculate the mol %ethylene and styrene in the interpolymers.${W\quad t\quad \% \quad E} = {\frac{E*28}{\left( {E*28} \right) + \left( {S_{c}*104} \right)}(100)}$and${W\quad t\quad \% \quad S} = {\frac{S_{c}*104}{\left( {E*28} \right) + \left( {S_{c}*104} \right)}(100)}$

[0111] where: s_(c) and e_(c) are styrene and ethylene proton fractionsin the interpolymer, respectively, and S_(c) and E are mole fractions ofstyrene monomer and ethylene monomer in the interpolymer, respectively.

[0112] The weight percent of aPS in the interpolymers was thendetermined by the following equation:${{Wt}\quad \% \quad a\quad P\quad S} = {\frac{\left( {W\quad t\quad \% \quad S} \right)*\left( \frac{\frac{A_{6.6}}{2}}{S\quad c} \right)}{100 + \left\lbrack {\left( {W\quad t\quad \% \quad S} \right)*\left( \frac{\frac{A_{6.6}}{2}}{S\quad c} \right)} \right\rbrack}*100}$

[0113] The total styrene content was also determined by quantitativeFourier Transform Infrared spectroscopy (FTIR).

[0114] Preparation of Ethylene/Styrene Interpolymers Used in Examplesand Comparative Experiments of Present Invention

[0115] ESI 1 and EPS-1 are substantially random interpolymers preparedusing the following polymerization procedure.

[0116] ESI 1 and EPS 1 were prepared in a continuously operating loopreactor. An Ingersoll-Dresser twin screw pump provided the mixing. Thereactor ran liquid full at 475 psig (3,275 kPa). Raw materials andcatalyst/cocatalyst flows were fed into the reactor through injectorsand Kenics static mixers in the loop reactor piping. From the dischargeof the loop pump, the process flow goes through two shell and tube heatexchangers before returning to the suction of the loop pump. Uponexiting the last exchanger, loop flow returned through the injectors andstatic mixers to the suction of the pump. A second monomer/feed injectorand mixer was used if available. Heat transfer oil or tempered water wascirculated through the exchangers' jacket to control the looptemperature. The exit stream of the loop reactor was taken off betweenthe two exchangers. The flow and solution density of the exit stream wasmeasured by a Micro-Motion™ mass flow meter.

[0117] Solvent was injected to the reactor primarily as part of the feedflow to keep the ethylene in solution. A split stream from thepressurization pumps prior to ethylene injection was taken to provide aflush flow for the loop reactor pump seals. Additional solvent is addedas a diluent for the catalyst. Feed solvent was mixed with uninhibitedstyrene monomer on the suction side of the pressurization pump. Thepressurization pump supplied solvent and styrene to the reactor atapproximately 650 psig (4,583 kPa). Fresh styrene flow was measured by aMicro-Motion™ mass flow meter, and total solvent/styrene flow wasmeasured by a separate Micro-Motion™ mass flow meter. Ethylene wassupplied to the reactor at approximately 690 psig (4,865 kPa). Theethylene stream was measured by a Micro-Motion™ mass flow meter. A flowmeter /controller was used to deliver hydrogen into the ethylene streamat the outlet of the ethylene control valve.

[0118] The ethylene/hydrogen mixture is at ambient temperature when itis combined with the solvent/styrene stream. The temperature of theentire feed stream as it entered the reactor loop was lowered toapproximately 2° C. by a glycol cooled exchanger. Preparation of thethree catalyst components took place in three separate tanks. Freshsolvent and concentrated catalyst/cocatalyst/secondary co-catalystpremix were added and mixed into their respective run tanks and fed intothe reactor via a variable speed Pulsafeeder™ diaphragm pumps. Aspreviously explained, the three component catalyst system entered thereactor loop through an injector and static mixer into the suction sideof the twin screw pump. The raw material feed stream was also fed intothe reactor loop through an injector and static mixer upstream of thecatalyst injection point or through a feed injector/mixer between thetwo exchangers, if available.

[0119] Polymerization was stopped with the addition of catalyst kill(water) into the reactor product line after the Micro-Motion™ mass flowmeter measuring the solution density. A static mixer in the lineprovided dispersion of the catalyst kill and additives in the reactoreffluent stream. This stream next entered post reactor heaters thatprovided additional energy for the solvent removal flash. This flashoccurred as the effluent exited the post reactor heater and the pressurewas dropped from 475 psig (3,275 kPa) down to approximately 450 mmHg (60kPa) of absolute pressure at the reactor pressure control valve.

[0120] This flashed polymer entered the devolatilization section of theprocess. The volatiles flashing from the devolatilization were condensedwith a glycol jacketed exchanger, passed through vacuum pump, and weredischarged to vapor/liquid separation vessel. In the first stage vacuumsystem, solvent/styrene were removed from the bottom of this vessel asrecycle solvent while unreacted ethylene exhausted from the top. Theethylene stream was measured with a Micro-Motion™ mass flow meter. Themeasurement of vented ethylene plus a calculation of the dissolved gasesin the solvent/styrene stream were used to calculate the ethyleneconversion. The polymer and remaining solvent was pumped with a gearpump to a final devolatilizer. The pressure in the second devolatilizerwas operated at approximately 10 mmHg (1.4 kPa) absolute pressure toflash the remaining solvent. The dry polymer (<1000 ppm total volatiles)was pumped with a gear pump to an underwater pelletizer with spin-dried,and collected. The preparation conditions for each sample are summarizedin Table 1. TABLE 1 Preparation Conditions for ESI 1 and EPS 1 ReactorSolvent Ethylene Propylene Hydrogen Styrene Ethylene ESI Temp Flow FlowFlow Flow Flow Conversion B/Ti MMAO^(e)/Ti Co- # ° C. lb/hr lb/hr lb/hrlb/hr lb/hr % Ratio Ratio Catalyst Catalyst ESI 1 115 21000 3120 N/A0.37 1480 94 5.4 8.2 A^(a) C^(c) NK02029 33A- EPS 1 130 725 100 6 0.00946 89 1.2 10 B^(b) D^(d) 382600 0529- 1900

[0121] TABLE 2 Blend Components Melt Flow Copolymer Copolymer CopolymerCopolymer Rate styrene styrene ethylene propylene Designation (dg/min)(wt %) (mol %) (wt %) (wt %) ESI-1 10* 30 10 70 — SBS-VECTOR ™  8* 43 —— 43 6241 (SBS 1) SBS- 20* 43 — — — SINGAPRENE ™ (SBS 2) PS-STYRON ™* 8** >97 — — >97 666D (PS) STYRON ™470  3** — — — (HIPS) EPS-1 10* 24 —71.4 4.6

[0122] Blends of ethylene styrene interpolymers (ESI 1) or ethylenepropylene styrene interpolymers (EPS 1) and polystrene (PS or HIPS)compatibilized with SBS block copolymer were injection molded.

[0123] Compounding: ESI, or EPS 1, SBS and PS or HIPS were first dryblended at certain weight ratios the compounded using a typical singlescrew (general purpose) extruder (2.5″) equipped with a under-waterpelletizer under the following conditions:

[0124] Zone temperature 400° F., Melt temperature 410° F., Dietemperature 400° F., Adapter temperature 400° F., Underwater cut watertemperature: 70° F., Output 250-300 pounds/hr, Residence Time 2 minutes

[0125] Injection Molding: A 150 tons DEMAG injection molding machine wasused. The typical molding conditions include:

[0126] Injection pressure: 1200-1500 psi, Injection time: 1-2 seconds,Hold pressure: 300-500 psi, Hold time: 2-5 seconds, Cooling time: 3-10seconds

[0127] Tensile Test: Tensile Bar made according to ASTM Method 638 wasused for measurement of ultimate tensile strength, yield tensile, %elongation.

[0128] Pull Force Test: The ⅛″ I.D. arm from a popular injection moldedDisney character Mickey Mouse was used for pull force evaluation. MickeyMouse made from various developmental toy resins as well as competitorswere tested on a standard Pull Force Gauge (Master Carr, 0-50 pounds at½ pound increments).

[0129] Paint Stripping Test: Two types of paint (ESI and TPE based—5colors each) from Rainbow Forest, China are used. Toy parts are firstspray painted, cure overnight, marked with sharp blade at 3 differentlocations (25 squares each), and then subjected to stripping with aadhesive tape. The number of squares stripped with the tape was used todetermine how good the paint adheres to the toy. A score of 5 means nosquare was stripped.

[0130] Cycle Time: The cycle time required to injection mold, withoutdistortion, a popular McDonald toy character HAMBURGLAR™ was used tocompare various developmental toy resins and to the competitors. Thismold was chosen due to its relatively thick body, which requires longercycle time. TABLE 3 Comparative Examples of ESI/HIPS blends (no SBS)*Tensile Strength Arm pull force* Cycle time** Comp Ex Blend Composition(psi) (lb) (sec) Paintability #1 100 wt % ESI 1632 20 >40 5 #2 90 wt %ESI/10 wt % HIPS 1507 17 >40 5 #3 80 wt % ESI/20 wt % HIPS 1190 17 >40 5#4 70 wt % ESI/30 wt % HIPS 1080 17 >40 5 #5 60 wt % ESI/40 wt % HIPS1036 18  37-40 5 #6 50 wt % ESI/50 wt % HIPS 1000 22  33-37 5

[0131] TABLE 4 Comparative Examples of ESI/SBS blend (no PS)* TensileStrength Arm pull force* Cycle time** Comp Ex Blend Composition (psi)(lb) (sec) Paintability #7 50 wt % ESI/50 wt % SBS1 2594 — 22 5

[0132] TABLE 5 Comparative Examples of SBS/HIPS blend (no ESI)* TensileStrength Arm pull force* Cycle time** Comp Ex Blend Composition (psi)(lb) (sec) Paintability #8 50 wt % SBS2/50 wt % HIPS 2603 — 37 4

[0133] TABLE 6 Comparative Examples of ESI/PS blends (no SBS)* TensileStrength Arm pull force* Cycle time** Comp Ex Blend Composition (psi)(lb) (sec) Paintability  #9 100 wt % ESI 1632 20 >40 5 #10 90 wt %ESI/10 wt % PS 1607 19 >40 5 #11 80 wt % ESI/20 wt % PS 1301 17 >40 5#12 70 wt % ESI/30 wt % PS 1205 17 37-40 5 #13 60 wt % ESI/40 wt % PS907 17 35-38 5 #14 50 wt % ESI/50 wt % PS 808 19 33-36 5

[0134] TABLE 7 Examples of ESI/SBS/HIPS blends* Tensile Strength Armpull force* Cycle time** Ex Blend Composition (psi) (lb) (sec)Paintability Comp Ex #15 50 wt % ESI/0 wt % SBS1/50 wt % HIPS 1000 2232-35 5 #1 40 wt % ESI/10 wt % SBS1/50 wt % HIPS 2220 39 20-22 5 #2 35wt % ESI/15 wt % SBS1/50 wt % HIPS 2300 38 17-18 5 #3 30 wt % ESI/20 wt% SBS1/50 wt % HIPS 2363 44 17-18 5 Comp Ex #16 60 wt % ESI/0 wt %SBS1/40 wt % HIPS 1036 18 22-25 5 #4 50 wt % ESI/10 wt % SBS1/40 wt %HIPS 1641 28 22-25 5 #5 45 wt % ESI/15 wt % SBS1/40 wt % HIPS 1922 3317-18 5 #6 40 wt % ESI/20 wt % SBS1/40 wt % HIPS 1929 35 17-18 5 #7 35wt % ESI/25 wt % SBS1/40 wt % HIPS 2060 38 17-18 5 #demonstrate theeffectiveness of SBS as compatibilizer between ESI and HIPS at 40 wt %HIPS level. As seen, as the SBS increased from 10% to 25%, the tensilestrength increased from 1641 (#4) to 2060 psi (#7), respectively.

[0135] TABLE 8 Examples of ESI/SBS/PS blends* Tensile Strength Arm pullforce* Cycle time** Ex Blend Composition (psi) (lb) (sec) PaintabilityComp Ex #17 50 wt % ESI/0 wt % SBS1/50 wt % PS 808 19 33-36 5  #8 45 wt% ESI/5 wt % SBS1/50 wt % PS 1789 33 22-25 5  #9 40 wt % ESI/10 wt %SBS1/50 wt % PS 2053 52 17-18 5 #10 37.5 wt % ESI/12.5 wt % SBS1/50 wt %PS 2389 56 17-18 5 #11 30 wt % ESI/20 wt % SBS1/50 wt % PS 2445 58 17-185 Comp Ex #18 60 wt % ESI/0 wt % SBS1/40 wt % PS 907 17 35-38 5 #12 50wt % ESI/10 wt % SBS1/40 wt % PS 2022 42 17-18 5 #13 48 wt % ESI/12 wt %SBS1/40 wt % PS 2213 47 17-18 5 #14 45 wt % ESI/15 wt % SBS1/40 wt % PS2261 48 17-18 5 #15 40 wt % ESI/20 wt % SBS1/40 wt % PS 2169 46 17-18 5#16 35 wt % ESI/25 wt % SBS1/40 wt % PS 2287 48 17-18 5 # 2445 psi asthe SBS increased to 20% (#11). Examples #12-#16 demonstrate theeffectiveness of SBS as compatibilizer between ESI and PS at 40 wt. % PSlevel. With 10% SBS addition, the tensile strength increased from 907(#18) to 2022 psi (#12). The # tensile strength continued to increase to2287 psi as 25% PS was added (#16).

[0136] TABLE 9 Example of EPS/SBS/PS blends Tensile Strength Arm pullforce* Cycle time** Ex Blend Composition (psi) (lb) (sec) PaintabilityComp Ex #19 100 wt % EPS 1432 18 >40 5 #17 40 wt % EPS/10 wt % SPS1/50wt % PS 2268 50 17-18 5 #18 48 wt % EPS/12 wt % SPS1/40 wt % PS 1936 4417-18 5

What is claimed is:
 1. A blend composition comprising; (A) one or morealkenyl aromatic polymers; (B) one or more substantially randominterpolymers comprising (1) from about 0.5 to about 15 mol percent ofpolymer units derived from; (a) at least one vinyl or vinylidenearomatic monomer, or (b) at least one hindered aliphatic orcycloaliphatic vinyl or vinylidene monomer, or (c) a combination of atleast one aromatic vinyl or vinylidene monomer and at least one hinderedaliphatic or cycloaliphatic vinyl or vinylidene monomer, and (2) fromabout 85 to about 99.5 mol percent polymer units derived from at leastone of ethylene and/or a C₃₋₂₀ α- olefin; and (3) from 0 to about 20 molpercent of polymer units derived from one or more of ethylenicallyunsaturated polymerizable monomers other than those derived from (1) and(2); and, (C) one or more compatibilizers; and wherein said blend has;a) a tensile strength greater than 1500 psi; b) a pull force test (⅛″diameter) greater than 15 lb; c) a Shore A Hardness greater than 79; d)a cycle time in injection molding of less than 30 sec.
 2. The blendcomposition of claim 1 wherein; A) Component A is present in an amountof from about 20 to about 70 percent by weight (based on the combinedweights of Components A, B and C; B) Component B is present in an amountof from about 20 to about 70 percent by weight (based on the combinedweights of Components A, B and C; C) Component C is present in an amountof from about 1 to about 30 percent by weight (based on the combinedweights of Components A, B and C) and wherein said blend has; a) atensile strength greater than 1700 psi; b) a pull force test (⅛″diameter) greater than 17 lb; c) a Shore A Hardness greater than 82; andd) a cycle time in injection molding of less than 28 sec.
 3. The blendcomposition of claim 1 wherein; A) Component A is selected from thegroup consisting of GPPS (general purpose polystyrene) and HIPS (highimpact polystyrene); B) Component B is selected from the groupconsisting of substantially random ethylene/styrene andethylene/propylene/styrene interpolymers; and; C) Component C isselected from the group consisting of SBS (styrene-butadiene-styrene) orSIS (styrene-isoprene-styrene) or SEBS(styrene-ethylene-butylene-styrene) or SEPS(styrene-ethylene-propylene-styrene) block copolymers or a substantiallyrandom interpolymer other than that of Component B; and wherein saidblend has; a) a tensile strength greater than 1900 psi; b) a pull forcetest (⅛″ diameter) greater than 21 lb; c) a Shore A Hardness greaterthan 84; and d) a cycle time in injection molding of less than 26 sec.4. The blend of claim 3 wherein said pull force test is greater than 40lb.
 5. An injection molded article having a paintability score of 5(according to ASTM Method D-3359), prepared from a blend compositioncomprising; (A) one or more alkenyl aromatic polymers; (B) one or moresubstantially random interpolymers comprising (1) from about 0.5 toabout 15 mol percent of polymer units derived from; (a) at least onevinyl or vinylidene aromatic monomer, or (b) at least one hinderedaliphatic or cycloaliphatic vinyl or vinylidene monomer, or (c) acombination of at least one aromatic vinyl or vinylidene monomer and atleast one hindered aliphatic or cycloaliphatic vinyl or vinylidenemonomer, and (2)) from about 85 to about 99.5 mol percent of polymerunits derived from at least one of ethylene and/or a C₃₋₂₀ α-olefin; and(3)) from 0 to about 20 mol percent of polymer units derived from one ormore of ethylenically unsaturated polymerizable monomers other thanthose derived from (1) and (2); and, (C) one or more compatibilizers;and wherein said blend has; a) a tensile strength greater than 1500 psi;b) a pull force test (⅛″ diameter) greater than 15 lb; c) a Shore AHardness greater than 79; d) a cycle times in injection molding of lessthan 30 sec.
 6. The injection molded article of claim 5 wherein; A) saidComponent A is present in an amount of from about 20 to about 70 percentby weight (based on the combined weights of Components A, B and C; B)said Component B is present in an amount of from about 20 to about 70percent by weight (based on the combined weights of Components A, B andC; and C) said Component C is present in an amount of from about 1 toabout 30 percent by weight (based on the combined weights of ComponentsA, B and C) and wherein said blend has; a) a tensile strength greaterthan 1700 psi; b) a pull force test (⅛″ diameter) greater than 17 lb; c)a Shore A Hardness greater than 82; and d) a cycle time in injectionmolding of less than 28 sec.
 7. The injection molded article of claim 5wherein A) said Component A is selected from the group consisting ofGPPS (general purpose polystyrene) and HIPS (high impact polystyrene);B) said Component B is selected from the group consisting ofsubstantially random ethylene/styrene and ethylene/propylene/styreneinterpolymers; and; C) said Component C is selected from the groupconsisting of SBS (styrene-butadiene-styrene) or SIS(styrene-isoprene-styrene) or SEBS (styrene-ethylene-butylene-styrene)or SEPS (styrene-ethylene-propylene-styrene) block copolymers or asubstantially random interpolymer other than that of Component B; andwherein said blend has; a) a tensile strength greater than 1900 psi; b)a pull force test (⅛″ diameter) greater than 21 lb; c) a Shore AHardness greater than 84; and d) a cycle time in injection molding ofless than 26 sec.
 8. The injection molded article of claim 7 whereinsaid pull force test is greater than 40 lb.
 9. The injection moldedarticle of claim 5 in the form of a toy, sports article, food container,household article, footware, automotive article, or an assemblyadhesive.